1. Technical Field
The present invention generally relates to wireless communications, and particularly relates to methods and apparatus for processing mobile station transaction information among base stations in a wireless communication system employing a distributed control architecture.
2. Background
As wireless network operators strive to increase the capacity and throughput of their networks, it is expected that cells in mobile communication systems will be deployed in a wide variety of sizes. In particular, many cells will be much smaller than in past systems. Network operators are already beginning to extensively deploy so-called micro-cells and pico-cells in, for example, shopping centers, city centers, and office areas.
At the same time, there is a trend to move radio network control functionality to the base station site in new network architectures. This is true, for example, in the Long Term Evolution (LTE) wireless communication systems currently under development by the 3rd-Generation Partnership Project (3GPP). Similar concepts are also being discussed with respect to the implementation of very small Radio Network Controllers (RNCs) for Evolved High-Speed Packet Access (HSPA) systems. Proponents of this trend suggest that locating resource control functionality at the base station site will result in better system performance, because more timely information will be available for radio resource management decisions.
On the other hand, network control procedures implemented in a centralized architecture, such as handover procedures in a conventional 3G RNC, can more readily exploit information regarding the situation in several neighboring cells as well as conditions in the current cell where a user equipment (UE) is located. The use of a distributed architecture, i.e., a system model where control functionality is pushed to the base stations, thus potentially creates a situation where the control function has a great deal of up-to-date knowledge of the local environment, but does not have the broader network overview that might be available in a centralized control function. In such a system, a handover procedure performed at an LTE base station (an eNodeB) might be based largely on limited information, such as status information for the current cell and any neighboring cells served by the same eNodeB.
Another potential problem with a distributed architecture model is that mobile user equipment may be controlled by several different controllers over a short period of time, as the user equipment is passed (handed over) from one base station to another. Although each controller (the eNodeB in the case of an LTE system) can monitor the activity of a specific mobile station while serving that mobile station, this information is generally lost when the mobile station is handed over to another controller. This is less of a problem in a system using a centralized control architecture, since a controller in such a system typically covers many cells, and a mobile station is generally controlled by the same controller for a longer period of time.